KR20240040030A - Inspection method of workpiece and inspection apparatus of workpiece - Google Patents

Abstract

(Problem) To provide a method and inspection device for inspecting a workpiece that can determine the peeling layer formed inside an ingot without reducing productivity and without being influenced by saw marks.
(Solution) A method of inspecting a workpiece includes performing a peeling layer forming step of forming a peeling layer consisting of a modified layer parallel to the upper surface and a crack extending from the modified layer inside the workpiece, and performing the peeling layer forming step, An irradiation step of irradiating the entire upper surface of the workpiece on which the peeling layer is formed with light of a wavelength that penetrates the workpiece and is reflected by cracks in the peeling layer, and the reflected light irradiated in the irradiation step and reflected by the cracks It includes a light receiving step of receiving light, and a determination step of determining the state of the peeling layer based on the intensity of the reflected light received in the light receiving step.

Description

Inspection method and inspection device for workpieces {INSPECTION METHOD OF WORKPIECE AND INSPECTION APPARATUS OF WORKPIECE}

The present invention relates to a method and inspection device for inspecting a workpiece made of single crystal silicon.

A wire saw is known as a means for cutting wafers from silicon ingots, compound semiconductor ingots, etc. In a wire saw, a wire row is formed by winding a large number of cutting wires around a plurality of rollers, and cutting the cutting wire at the wire position by cutting and feeding the cutting wire with respect to the ingot (for example, patent document 1 reference). However, the cutting allowance of the wire saw is relatively large, around 300㎛, and since it is necessary to perform lapping, etching, and polishing to flatten the surface after cutting, the amount of material used as a wafer is about 1/3 of the original ingot. There was a problem that productivity was low.

Therefore, a technology was devised to form a peeling layer consisting of modified portions and cracks inside the ingot by irradiating a laser beam to the ingot, and to peel the wafer from the ingot using this peeling layer as a starting point (see Patent Document 2). . This makes it possible to significantly reduce material loss compared to a wire saw. However, when peeling using the peeling layer as a starting point, the peeling layer cannot be peeled due to insufficient formation of the peeling layer or peeling treatment (application of ultrasonic waves, etc.). I found out there was a case.

Therefore, in order to specify the area where the peeling layer is not formed and perform additional processing or peeling treatment, a method was devised to detect the peeling layer formed inside the ingot by irradiating light to the ingot (patent document 3, 4).

Patent Document 1: Japanese Patent Publication No. 09-262826 Patent Document 2: Japanese Patent Publication No. 2022-025566 Patent Document 3: Japanese Patent Publication No. 2021-068819 Patent Document 4: Japanese Patent Publication No. 2018-147928

However, in the method of Patent Document 3, since the condensing lens and the peeling layer detection unit are installed adjacent to each other along a direction parallel to the processing transfer direction, an area that cannot be detected occurs when laser processing is completed. Therefore, even though processing is completed, it is necessary to overrun the condensing lens and the peeling layer detection unit to detect the peeling layer, which may lead to a decrease in productivity due to an increase in the diameter of the ingot. In addition, the method of Patent Document 4 uses the so-called magic principle to determine the state of the peeling layer formed inside the ingot, but there is a problem that it is easily affected by saw marks on the ingot surface.

Therefore, an object of the present invention is to provide a method and inspection device for inspecting a workpiece that can determine the peeling layer formed inside an ingot without reducing productivity and without being influenced by saw marks.

According to one aspect of the present invention, a method for inspecting a workpiece made of single crystal silicon manufactured so that a specific crystal plane included in the crystal plane {100} is exposed on each of the upper and lower surfaces, comprising:

The condensing point of the laser beam having a wavelength that is transparent to the workpiece is positioned at a depth corresponding to the thickness of the wafer to be manufactured from the upper surface of the workpiece, and the focus point and the workpiece are moved in a relative processing transfer direction. A peeling layer forming step of irradiating a laser beam while moving to form a modified layer parallel to the upper surface inside the workpiece and a crack extending from the modified layer;

After performing the peeling layer forming step, an irradiation step of irradiating light of a wavelength that transmits through the workpiece and is reflected from cracks in the peeling layer to the entire upper surface of the workpiece on which the peeling layer is formed;

a light receiving step of receiving reflected light irradiated in the irradiation step and reflected by the crack;

A method for inspecting a workpiece is provided, including a determination step of determining the state of the peeling layer based on the intensity of reflected light received in the light receiving step.

Preferably, in the determination step, it is determined whether or not adjacent cracks in the peeling layer are connected to each other based on whether the reflected light intensity is greater than a first predetermined value,

If it is determined in the determination step that the adjacent cracks in the peeling layer are connected, a peeling step is performed in which an external force is applied to the workpiece to peel the wafer from the workpiece using the peeling layer as a starting point.

Preferably, after performing the peeling layer forming step, a peeling step is performed in which an external force is applied to the workpiece to peel the wafer from the workpiece using the peeling layer as a starting point.

Preferably, when the wafer cannot be peeled from the workpiece in the peeling step, the irradiation step, the light receiving step, and the determination step are performed again.

Preferably, in the determination step, the intensity of the reflected light is determined by whether or not the intensity of the reflected light is greater than a second predetermined value that is greater than the first predetermined value, which is a criterion for determining whether adjacent cracks in the peeling layer are connected and formed. It is determined whether or not the wafer is peeled from the workpiece using the layer as a starting point.

Preferably, the peeling layer forming step irradiates the laser beam while relatively moving the converging point of the laser beam and the workpiece along a direction parallel to the crystal orientation <100>, and radiates the laser beam to the inside of the workpiece. A laser beam irradiation step of forming a modified layer parallel to the upper surface and a crack extending from the modified layer, and forming the laser beam at the convergence point and the By alternately performing the indexing transfer steps of relatively indexing and transferring the workpiece, a peeling layer including a plurality of modified layers and cracks is formed inside the workpiece.

Preferably, the light irradiated in the irradiation step is irradiated to the upper surface of the workpiece at a predetermined angle of incidence from a direction parallel to a plane perpendicular to the upper surface of the workpiece, including the processing transfer direction.

According to another aspect of the present invention, a laser beam having a wavelength having transparency is irradiated from the upper surface side to a workpiece made of single crystal silicon manufactured so that a specific crystal plane included in the crystal plane {100} is exposed on each of the upper surface and the lower surface. An inspection device for inspecting the peeling layer of a workpiece in which a peeling layer consisting of a modified layer and cracks extending from the modified layer is formed inside the workpiece,

A holding table that exposes the upper surface of the workpiece to hold the workpiece,

a light source that irradiates light of a wavelength that passes through the workpiece and is reflected from the crack to the entire upper surface of the workpiece held on the holding table;

a light receiving unit that is illuminated by the light source to the entire upper surface of the workpiece and receives reflected light reflected from the crack included in the peeling layer;

An inspection device is provided including a determination unit that determines the state of the peeling layer based on the intensity of reflected light received by the light receiving unit.

Preferably, the determination unit determines whether or not adjacent cracks in the peeling layer are connected to each other, based on whether or not the reflected light intensity is greater than the first predetermined value.

Preferably, the determination unit determines whether the intensity of the reflected light is greater than a second predetermined value that is greater than the first predetermined value, which is a criterion for determining whether adjacent cracks in the peeling layer are connected and formed, It is determined whether or not the wafer is peeled from the workpiece using the layer as a starting point.

Preferably, the workpiece is irradiated with a laser beam along a direction parallel to the crystal orientation <100> to form a peeling layer including a modified layer parallel to the upper surface and cracks extending from the modified layer. There is,

The light source is located at a position capable of irradiating light to the upper surface of the workpiece at a predetermined angle of incidence from a direction parallel to a plane perpendicular to the top surface of the workpiece, including the processing transport direction, which is the direction in which the laser beam is irradiated. It is placed.

Preferably, at least two light sources are arranged.

The present invention irradiates the entire upper surface of the workpiece with light of a wavelength that passes through the workpiece and is reflected by the peeling layer, and observes the intensity of the reflected light reflected from the peeling layer. Because the state of the internal peeling layer is determined, the state of the peeling layer can be determined just by irradiating light once on the entire upper surface of the workpiece, regardless of the size of the workpiece, without reducing productivity. , it becomes possible to determine the peeling layer in a short time.

In addition, the present invention determines the formation situation of the peeling layer, more specifically, whether adjacent cracks are connected to each other, depending on the intensity of the reflected light, and whether the connected cracks expand and the ingot side and the wafer side of the workpiece are separated. Since it is possible to determine whether it exists or not, the state of the peeling layer can be determined without being influenced by saw marks.

Fig. 1 is a perspective view showing an example of a workpiece to be inspected by the inspection method and inspection device for the workpiece according to the first embodiment.
FIG. 2 is a top view showing the workpiece of FIG. 1.
FIG. 3 is a flowchart showing the processing sequence of the inspection method for a workpiece according to the first embodiment.
FIG. 4 is a side view showing the peeling layer forming step in FIG. 3.
FIG. 5 is a perspective view showing the peeling layer forming step in FIG. 3.
FIG. 6 is a side view illustrating an example of the configuration of the inspection device according to the first embodiment and an example of the irradiation step and the light receiving step in FIG. 3.
FIG. 7 is a side view showing another example of the configuration of the inspection device according to the first embodiment and another example of the irradiation step and the light receiving step in FIG. 3.
FIG. 8 is a diagram showing the determination step in FIG. 3.
FIG. 9 is a top view showing an example of the determination step in FIG. 3.
Figure 10 is a perspective view showing the peeling step in Figure 3.
Figure 11 is a perspective view showing the peeling step in Figure 3.
FIG. 12 is a flowchart showing the processing sequence of the inspection method for a workpiece according to the second embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the content described in the following embodiments. In addition, the components described below include those that can be easily assumed by those skilled in the art and those that are substantially the same. Additionally, the configurations described below can be combined appropriately. Additionally, various omissions, substitutions, or changes in the structure may be made without departing from the gist of the present invention.

[First Embodiment]

The inspection method and inspection devices 1 and 1-2 for a workpiece according to the first embodiment of the present invention will be explained based on the drawings.

FIG. 1 is a perspective view showing an example of a workpiece 100 to be inspected by the workpiece inspection method and inspection apparatus 1 and 1-2 according to the first embodiment. FIG. 2 is a top view showing the workpiece 100 of FIG. 1 . As shown in FIG. 1, the workpiece 100 is a Si (silicon) ingot made of single crystal silicon manufactured so that a specific crystal plane included in the crystal plane {100} is exposed to the upper surface 101 and the lower surface 102, respectively. .

As shown in FIGS. 1 and 2, the workpiece 100 is formed as a whole in a cylindrical shape in the first embodiment, and has a circular upper surface ( 101), a circle-shaped lower surface 102 on the opposite side from the upper surface 101, with the same specific crystal surface as the upper surface 101 as a flat surface, and a perimeter located between the upper surface 101 and the lower surface 102. It has a face (103). In the first embodiment, the upper surface 101 and the lower surface 102 are flat surfaces of a specific crystal plane 100 included in the crystal plane {100}, as shown in FIG. 2, but the present invention is not limited to this. Alternatively, the crystal plane (010) or crystal plane (001) may be a flat surface.

As shown in FIGS. 1 and 2 , a flat rectangular orientation flat 104 is formed on the peripheral surface 103 of the workpiece 100 . In the first embodiment, the orientation flat 104 is located on the crystal plane (011) at a position where the central axis 105 of the workpiece 100 is located in the direction of the crystal orientation [011], as shown in FIG. They are formed in parallel. In addition, the workpiece 100 is not limited to this in the present invention, and a notch extending in the axial direction may be formed on the peripheral surface 103 at the same position instead of the orientation flat 104.

Next, this specification explains the inspection method of the workpiece according to the first embodiment based on the drawings. FIG. 3 is a flowchart showing the processing sequence of the inspection method for a workpiece according to the first embodiment. The inspection method of the workpiece according to the first embodiment is a method of inspecting the workpiece 100, and includes a peeling layer forming step (1001), an irradiation step (1002), a light receiving step (1003), and a judgment step. (1004) and a peeling step (1006).

FIGS. 4 and 5 are cross-sectional views and perspective views, respectively, illustrating the peeling layer forming step 1001 of FIG. 3 . In the peeling layer forming step 1001, as shown in FIGS. 4 and 5, the condensing point 59 of the laser beam 58 of a wavelength having transparency to the workpiece 100 is formed on the workpiece 100. It is positioned at a depth 120 corresponding to the thickness of the wafer to be manufactured from the surface 101, and the laser beam 58 is irradiated while moving the converging point 59 and the workpiece 100 relatively in the processing transfer direction. Thus, this is a step of forming a peeling layer 110 including a modified layer parallel to the upper surface 101 and a crack extending from the modified layer inside the workpiece 100.

In the first embodiment, the peeling layer forming step 1001 is performed by the laser processing device 50 shown in FIGS. 4 and 5. As shown in FIGS. 4 and 5, the laser processing device 50 includes a holding table 51 that holds the workpiece 100 with a holding surface 52, a laser oscillator 53, and an output adjustment unit. It is provided with (54), a branch unit 55, a mirror 56, a concentrator 57, a moving unit not shown, and a controller not shown.

The holding table 51 is, for example, a chuck table that exposes the upper surface 101 side of the workpiece 100 on the holding surface 52 and holds it by suction from the lower surface 102 side. The laser oscillator 53 emits a laser beam 58 with a wavelength that has transparency to the workpiece 100. The output adjustment unit 54 adjusts the output of the laser beam 58 emitted from the laser oscillator 53. The branching unit 55 branches the laser beam 58, the output of which has been adjusted by the output adjustment unit 54, into a plurality of beams (five in the example shown in FIG. 4) at predetermined intervals in the Y-axis direction. The mirror 56 changes the optical path by reflecting the plurality of laser beams 58 branched by the branching unit 55. The concentrator 57 condenses the plurality of laser beams 58 reflected by the mirror 56 and irradiates them to the workpiece 100.

The moving unit includes a holding table 51, a workpiece 100 held on the holding table 51, a concentrator 57, and a condensing point 59 of a plurality of laser beams 58 formed by the concentrator 57. ) is relatively moved along the machining feed direction and the indexing feed direction. Here, in the first embodiment, the processing transfer direction is the X-axis direction of the laser processing device 50, and the indexing transfer direction is the Y-axis direction of the laser processing device 50.

The controller of the laser processing device 50 controls the operation of each component of the laser processing device 50 and causes the laser processing device 50 to perform the peeling layer forming step 1001. The controller of the laser processing device 50 includes the same computer system as the controller of the inspection device 1 described later.

In the peeling layer forming step 1001, first, the controller of the laser processing device 50 transfers the workpiece 100 onto the holding table 51 by a transfer unit (not shown), and places the workpiece 100 on the holding table 51. The workpiece 100 is maintained by.

In the peeling layer forming step 1001, the controller of the laser processing device 50 rotates the holding table 51 around the Z-axis, etc. to remove the workpiece 100 held by the holding table 51. A specific crystal orientation parallel to the upper surface 101 and included in the crystal orientation <100> is aligned with the processing transfer direction.

In the first embodiment, the controller of the laser processing device 50 adjusts the specific crystal orientation [010] of the workpiece 100 to the processing transfer direction, but the present invention is not limited to this and the A specific crystal orientation [001] may be aligned with the processing transfer direction.

In the first embodiment, the peeling layer forming step 1001 includes a laser beam irradiation step 1011 and an indexing transfer step 1012, as shown in FIG. 3 . In the peeling layer forming step 1001, the workpiece 100 is held by the holding table 51, the specific crystal orientation of the workpiece 100 is adjusted to the processing transfer direction, and then the laser beam irradiation step 1011 is performed. By performing the indexing transfer steps 1012 alternately, a peeling layer 110 including a plurality of modified layers and cracks is formed inside the workpiece 100.

In the laser beam irradiation step 1011, the controller of the laser processing device 50 moves the converging point 59 of the laser beam 58 and the workpiece 100 in the processing transfer direction, that is, the workpiece 100. While moving along a direction parallel to the upper surface 101 of (100) and parallel to a specific crystal orientation included in the crystal orientation <100> (in the first embodiment, the crystal orientation [010]), the concentrator 57 This is a step of forming a modified layer parallel to the upper surface 101 and a crack extending from the modified layer inside the workpiece 100 by irradiating the laser beam 58.

When the workpiece 100 is irradiated with the laser beam 58 in the laser beam irradiation step 1011, the converging point of the laser beam 58 is formed along a line parallel to the processing transfer direction in which the laser beam 58 is irradiated ( A modified layer parallel to the upper surface 101 is formed near 59), and cracks extending along a direction parallel to the upper surface 101 are formed from both sides of the modified layer. Additionally, the modified layer is a region in which, for example, density, refractive index, mechanical strength or other physical properties are different from those of the surrounding area.

In the indexing transfer step 1012, the controller of the laser processing device 50 moves the laser beam in the indexing transfer direction, that is, a direction orthogonal to the direction in which the modified layer was formed in the laser beam irradiation step 1011, by a moving unit. This is a step of relatively indexing and transferring the converging point 59 of the beam 58 and the workpiece 100.

By performing the laser beam irradiation step 1011 and the indexing transfer step 1012 alternately, the workpiece 100 is aligned at the condensing point of the laser beam 58 along a plurality of lines parallel to the processing transfer direction ( A modified layer parallel to the upper surface 101 is formed near 59), and cracks extended from the modified layer formed along adjacent lines are connected to each other. As a result, the workpiece 100, by applying a predetermined external force, has the peeling layer 110 containing these modified layers and cracks as a starting point, and has a depth 120 corresponding to the upper surface 101. Wafers of any thickness can be peeled.

FIG. 6 is a cross-sectional view illustrating an example of the configuration of the inspection device 1 according to the first embodiment and an example of the irradiation step 1002 and the light receiving step 1003 in FIG. 3. FIG. 7 is a cross-sectional view illustrating another example of the configuration of the inspection device 1-2 according to the first embodiment and another example of the irradiation step 1002 and the light receiving step 1003 in FIG. 3. FIG. 8 is a diagram illustrating the determination step 1004 in FIG. 3. FIG. 9 is a top view showing an example of the determination step 1004 in FIG. 3. In the first embodiment, the irradiation step 1002, the light reception step 1003, and the determination step 1004 are performed using the inspection device 1 according to the first embodiment shown in FIG. 6 or the test device 1 shown in FIG. 7. This is carried out using the inspection device 1-2 according to the first embodiment.

The inspection device 1 according to the first embodiment is provided with a workpiece 100 made of single crystal silicon manufactured so that a specific crystal plane included in the crystal plane {100} is exposed to each of the upper surface 101 and the lower surface 102. A laser beam 58 having a wavelength having transparency is irradiated from the upper surface 101 side, so that a peeling layer 110 consisting of a modified layer and a crack extending from the modified layer is formed inside the workpiece 100. It is an apparatus for inspecting the peeling layer 110 of (100), and is an apparatus for performing the irradiation step (1002), the light reception step (1003), and the judgment step (1004) of the inspection method of the workpiece according to the first embodiment. .

As shown in FIG. 6, the inspection device 1 according to the first embodiment includes a holding table 10, a light source 20, a light receiving unit 30, and a determination unit 40. It is provided with a cover not shown and a display unit not shown.

The holding table 10 holds the workpiece 100 by exposing the upper surface 101 side of the workpiece 100 . In the first embodiment, the holding table 10 is a so-called chuck table having a disk-shaped frame body in which a concave portion is formed, and a disk-shaped suction portion fitted into the concave portion.

The suction portion of the holding table 10 is made of porous ceramic or the like having a large number of porous holes, and is connected to a vacuum suction source not shown through a vacuum suction path not shown. As shown in FIG. 6, the upper surface of the suction part of the holding table 10 holds the workpiece 100 on which it is placed, and the placed workpiece 100 is suctioned and held by the negative pressure introduced from the vacuum suction source. It is cotton (11).

In the first embodiment, the holding surface 11 holds the workpiece 100 with the upper surface 101 facing upward, and suction holds the placed workpiece 100 from the lower surface 102 side. The holding surface 11 and the upper surface of the frame of the holding table 10 are arranged on the same plane and are formed parallel to the XY plane, which is a horizontal plane.

The holding table 10 is installed so as to be rotatable about an axis parallel to the Z-axis direction, which is vertical and perpendicular to the holding surface 11 by a rotational drive source (not shown). In the first embodiment, the holding table 10 is rotated by a rotational drive source to irradiate the laser beam 58 to the workpiece 100 held on the holding table 10. The machining transfer direction can be aligned with the X-axis direction of the inspection device 1.

In addition, the processing transfer direction, which is the direction in which the laser beam 58 is irradiated to the workpiece 100, is the direction of the laser beam 58 in the workpiece 100 in the laser beam irradiation step 1011. It is the direction in which the light converging point 59 is relatively moved, that is, it is parallel to the upper surface 101 of the workpiece 100 and is a specific crystal orientation included in the crystal orientation <100> (in the first embodiment, the crystal orientation [ 010]) and is parallel to the direction.

The light source 20 transmits light 25 of a wavelength that penetrates the workpiece 100 and reflects through cracks on the entire upper surface 101 of the workpiece 100 held on the holding table 10. investigate.

As the light source 20, for example, a halogen light that emits infrared rays or a light emitting diode that emits infrared rays with a wavelength of 1450 nm is used. In the first embodiment, the light source 20 is positioned at a position to irradiate the light 25 to the entire upper surface 101 of the workpiece 100 from a direction parallel to the X-axis direction of the inspection device 1. It is installed.

That is, the light source 20, as described above, in the workpiece 100 held on the holding table 10, determines the processing transfer direction, which is the direction in which the laser beam 58 is irradiated to the workpiece 100, through the inspection device 1. ), by aligning with the It is placed in a position where it is possible to irradiate light 25. Here, in the first embodiment, the predetermined angle of incidence is, for example, 20 degrees or more and 70 degrees or less.

The light receiving unit 30 is irradiated to the entire upper surface 101 of the workpiece 100 by the light source 20 and receives the reflected light 35 reflected from the crack included in the peeling layer 110. In the first embodiment, the light receiving unit 30 is installed opposite to the central area of the upper surface 101 of the workpiece 100 held on the holding table 10, and It has a light-receiving field of view that covers the entire upper surface 101 of the workpiece 100, and is included in the entire surface of the peeling layer 110 of the workpiece 100 held on the holding table 10 with one light receiving treatment. The intensity distribution of the reflected light 35 from the crack can be acquired.

Here, the intensity distribution of the reflected light 35 from the crack included in the entire surface of the peeling layer 110 of the workpiece 100 held on the holding table 10 is determined by the location where the reflected light 35 is received and the reflected light ( This is data that corresponds to the intensity of 35).

In addition, the intensity distribution of the reflected light 35 from the crack contained in the entire surface of the peeling layer 110 of the workpiece 100 held on the holding table 10 is determined by the position where the reflected light 35 is received. It is indicated by each position projected on the upper surface 101 of the workpiece 100 held on the table 10, and includes the entire surface of the upper surface 101 of the workpiece 100 held on the holding table 10. . In addition, in the following, the intensity distribution of the reflected light 35 from the crack contained in the entire surface of the peeling layer 110 of the workpiece 100 held on the holding table 10 is appropriately referred to as the reflected light 35. It is called the intensity distribution of the entire surface.

The light receiving unit 30 is provided with an imaging element that captures an image of the entire upper surface 101 of the workpiece 100 held on the holding table 10, for example. The imaging device is, for example, a CCD (Charge-Coupled Device) imaging device or a CMOS (Complementary MOS) imaging device. The light receiving unit 30 can acquire an image 200 (see FIG. 9) of the intensity distribution of the entire surface of the reflected light 35. In the first embodiment, the image 200 has luminance according to the height of the intensity of the reflected light 35, that is, the location where the intensity of the reflected light 35 is high has high luminance, and the location where the intensity of the reflected light 35 is low has high luminance. is displayed with low brightness.

The determination unit 40 determines the state of the peeling layer 110 based on the intensity of the reflected light 35 received by the light receiving unit 30. The determination unit 40 is electrically connected to enable information communication with the light receiving unit 30, acquires the intensity distribution of the entire surface of the reflected light 35 from the light receiving unit 30, and determines the intensity distribution of the entire surface of the reflected light 35 based on this intensity distribution. , the state of the peeling layer 110 is determined for each position projected on the upper surface 101 of the workpiece 100 held on the holding table 10.

The intensity of the reflected light 35 received by the light receiving unit 30 changes depending on the state of the peeling layer 110 of the workpiece 100, as shown in FIG. 8 . A in FIG. 8 shows a case where the workpiece 100 is not processed. In this case, since there is nothing inside the workpiece 100 to reflect the light 25 from the light source 20, The intensity of the reflected light 35 received by the light receiving unit 30 is very weak.

B in FIG. 8 shows a case where the workpiece 100 is irradiated with the laser beam 58 to form a peeling layer 110 including a modified layer and cracks, but adjacent cracks in the modified layer are not connected to each other. In this case, the cracks inside the workpiece 100 reflect the light 25, but the portions where the cracks are not connected do not reflect the light 25, so the reflected light 35 received by the light receiving unit 30 )'s strength is relatively weak.

C in FIG. 8 shows a case where the workpiece 100 is irradiated with the laser beam 58 to form a peeling layer 110 including a modified layer and cracks, and adjacent cracks of the modified layer are connected to each other but are not peeled off. In this case, since the cracks inside the workpiece 100 and the parts where the cracks are connected reflect the light 25, the intensity of the reflected light 35 received by the light receiving unit 30 is relatively strong.

D in FIG. 8 shows a case where the workpiece 100 is irradiated with the laser beam 58 to form a peeling layer 110 containing a modified layer and cracks, and adjacent cracks of the modified layer are connected to each other and separated. In this case, since the peeled portion inside the workpiece 100 strongly reflects the light 25, the intensity of the reflected light 35 received by the light receiving unit 30 is very strong.

In particular, in the case where the cracks are connected to each other in the peeling layer 110 but are not separated, and in the case where the cracks are peeled off in the peeling layer 110, the intensity of the reflected light 35 is greatly different, and the latter is the reflected light. The intensity of (35) increases.

When the cracks are connected but not separated, there is a gap between the side including the lower surface 102 (ingot side) and the upper surface 101 (wafer side) of the workpiece 100, for example, There is almost no gap of about 1 μm or less, and since this gap is smaller than the wavelength of the light 25 from the light source 20, light 25 is generated that passes through the crack.

On the other hand, in the case of peeling, there is a space between the side including the lower surface 102 (ingot side) of the workpiece 100 and the side including the upper surface 101 (wafer side), for example, 5 μm or more and 20 μm. A gap of the following size is created, and since this gap is filled with air or water, the light 25 from the light source 20 is completely reflected without passing through this gap, becoming reflected light 35.

In this way, since the intensity of the reflected light 35 received by the light receiving unit 30 changes depending on the state of the peeling layer 110 of the workpiece 100, the determination unit 40 uses this to receive light. The state of the peeling layer 110 can be determined based on the intensity of the reflected light 35 received by the unit 30.

The determination unit 40 pre-registers the intensity of the reflected light 35 corresponding to the boundary between B and C in FIG. 8 as the first predetermined value 41, and registers the intensity of the reflected light 35 corresponding to the boundary between C and D in FIG. 8. The intensity of the reflected light 35 is pre-registered as the second predetermined value 42, and the intensity of the reflected light 35 corresponding to the boundary between A and B in FIG. 8 is pre-registered as the third predetermined value 43. It is done.

The first predetermined value 41 is smaller than the second predetermined value 42 and larger than the third predetermined value 43. The second predetermined value 42 is greater than the first predetermined value 41 and greater than the third predetermined value 43. The third predetermined value 43 is smaller than the first predetermined value 41 and smaller than the second predetermined value 42. The first predetermined value 41, the second predetermined value 42, and the third predetermined value 43 also change depending on the irradiation intensity or irradiation conditions of the light 25 from the light source 20, and the light receiving unit ( Since it also changes depending on the light receiving conditions of the reflected light 35 by 30), a sample of the unprocessed workpiece 100 prepared in advance, a workpiece 100 with a peeling layer 110 formed but the cracks are not connected to each other A sample of the workpiece 100 with cracks connected to each other but not separated, and a sample of the workpiece 100 that is peeled are examined and registered in advance in the judgment unit 40.

The determination unit 40 uses the pre-registered first predetermined value 41, second predetermined value 42, and third predetermined value 43 to determine the reflected light 35 received by the light receiving unit 30. The state of the peeling layer 110 of the workpiece 100 is determined based on the strength of .

The determination unit 40 determines whether adjacent cracks in the peeling layer 110 are connected to each other based on whether the intensity of the reflected light 35 is greater than the first predetermined value 41. That is, the first predetermined value 41 is a criterion for determining whether adjacent cracks of the peeling layer 110 are connected to each other.

Additionally, the determination unit 40 determines whether or not the wafer is separated from the workpiece 100 using the peeling layer 110 as a starting point based on whether the intensity of the reflected light 35 is greater than the second predetermined value 42. Judge. That is, the second predetermined value 42 is a criterion for determining whether or not the wafer is peeled from the workpiece 100 with the peeling layer 110 as a starting point.

The determination unit 40 determines whether the intensity of the reflected light 35 is greater than the third predetermined value 43 and determines whether the processing for forming the peeling layer 110 (e.g., laser processing in the peeling layer forming step 1001) ) is being performed or not. That is, the third predetermined value 43 is a judgment standard for whether or not processing to form the peeling layer 110 is being performed.

A cover (not shown) is arranged to cover the holding table 10, the light source 20, and the light receiving unit 30, and is made of a material that blocks light from the outside. The cover (not shown) blocks light from the outside, thereby increasing the precision of the intensity of the reflected light 35 received by the light receiving unit 30, and the peeling layer of the workpiece 100 by the judgment unit 40. The precision of determination of the state of (110) can be increased.

The display unit, not shown, is installed on a cover, not shown, of the inspection device 1 with the display side facing outward, and reflects the entire surface of the reflected light 35 acquired by the light receiving unit 30 of the inspection device 1. An image 200 of the intensity distribution, an image showing a decision result by the judgment unit 40 based on this intensity distribution, etc. are displayed so that the operator can see them.

The display unit is comprised of a liquid crystal display device or the like. The display unit is provided with an input unit used by the operator to input command information regarding various operations of the inspection device 1, irradiation conditions of the light 25, light reception conditions of the reflected light 35, image display, etc. there is.

The input unit installed in the display unit is comprised of at least one of a touch panel installed in the display unit, a keyboard, etc. In addition, the display unit is not fixed to the inspection device 1, but is provided in any communication device, and any communication device may be connected to the inspection device 1 wirelessly or by wire.

The inspection device 1 according to the first embodiment includes a controller not shown. The controller of the inspection device 1 controls the operation of each component of the inspection device 1 and causes the inspection device 1 to perform the irradiation step 1002, the light reception step 1003, and the judgment step 1004. .

The controller of the inspection device 1 includes a computer system in the first embodiment. The computer system included in the controller of the inspection device 1 includes an arithmetic processing unit having a microprocessor such as a CPU (Central Processing Unit), and a memory having memory such as ROM (Read Only Memory) or RAM (Random Access Memory). It has a device and an input/output interface device.

The arithmetic processing unit of the controller of the inspection device 1 performs arithmetic processing according to a computer program stored in the memory device of the controller of the inspection device 1 and provides a control signal for controlling the inspection device 1, It is output to each component of the inspection device (1) through the input/output interface device of the controller of the inspection device (1). In the first embodiment, the function of the judgment unit 40 is realized by the arithmetic processing unit of the controller of the inspection device 1 executing a computer program stored in a storage device.

As shown in FIG. 7, the inspection device 1-2 according to the first embodiment includes at least two light sources 20 (FIG. 7). In the example shown in , it has been increased to 2), and other configurations are the same.

Since the inspection device 1-2 according to the first embodiment has a plurality of light sources 20, it can obtain the amount of light 25 and can obtain the upper surface 101 of the workpiece 100. ) Since the uniformity of the light 25 irradiated to the entire surface is improved, the amount of reflected light 35 received by the light receiving unit 30 can be obtained, and the peeling layer of the workpiece 100 ( The uniformity of the reflected light 35 from the crack included in the entire surface of the 110 can be improved, thereby improving the determination of the state of the peeling layer 110 of the workpiece 100 by the determination unit 40. Precision can be increased.

In the irradiation step 1002, as shown in FIGS. 6 and 7, light 25 of a wavelength that transmits through the workpiece 100 and reflects from cracks in the peeling layer 110 is applied to the peeling layer 110. This is a step of examining the entire upper surface 101 of the formed workpiece 100.

In the irradiation step 1002, first, the controller of the inspection device 1, 1-2 transfers the workpiece 100 onto the holding table 10 by a transfer unit (not shown), etc. The workpiece 100 is maintained by . In the inspection step 1002, the controller of the inspection device 1, 1-2 holds the holding table 10 on the holding table 10, such as by rotating the holding table 10 around the Z axis using a rotation drive source. In the processed workpiece 100, the processing transfer direction, which is the direction in which the laser beam 58 is irradiated to the workpiece 100, is aligned with the X-axis direction of the inspection device 1.

In the irradiation step 1002, and in the first embodiment, the controller of the inspection device 1, 1-2 irradiates the inspection device 1 by the light source 20, as shown in FIGS. 6 and 7. ) The light 25 is irradiated to the entire surface of the upper surface 101 of the workpiece 100 from a direction parallel to the X-axis direction.

In the irradiation step 1002, the upper surface 101 of the workpiece 100 is measured at a predetermined angle of incidence from a direction parallel to a plane perpendicular to the top surface 101 of the workpiece 100, including the processing transfer direction. Since the light 25 is irradiated to the light 25, the flicker of the reflected light 35, which is the light reflected by the crack, is suppressed, and the light received by the light receiving unit 30 in the light receiving step 1003 to be performed later is suppressed. The reflected light 35 can be made clearer.

The light receiving step 1003 is a step of receiving the reflected light 35 irradiated in the irradiating step 1002 and reflected by the crack. In the light receiving step 1003, the controller of the inspection apparatus 1, 1-2 controls the holding table 10 by the light receiving unit 30 and the light source 20, as shown in FIGS. 6 and 7. Irradiating the entire surface of the upper surface 101 of the workpiece 100 held in and receiving the reflected light 35 reflected from the crack included in the peeling layer 110, the intensity distribution of the entire surface of the reflected light 35 acquire.

The determination step 1004 is a step of determining the state of the peeling layer 110 based on the intensity of the reflected light 35 received in the light receiving step 1003. In the determination step 1004, the determination unit 40 determines whether the intensity of the reflected light 35 received in the light receiving step 1003 is greater than the first predetermined value 41, and determines whether or not an adjacent crack in the peeling layer 110 is formed. Determines whether or not the elements are connected.

In the decision step 1004, the decision unit 40 determines whether the intensity of the reflected light 35 received in the light receiving step 1003 is greater than the second predetermined value 42, and determines whether the intensity of the reflected light 35 received in the light receiving step 1003 is greater than the second predetermined value 42. It is determined whether or not the wafer is peeled from the workpiece 100.

In the determination step 1004, the determination unit 40 determines whether or not processing to form the peeling layer 110 is being performed based on whether the intensity of the reflected light 35 is greater than the third predetermined value 43. do.

In the determination step 1004, for example, when the determination unit 40 acquires the image 200 shown in FIG. 9 as the intensity distribution of the entire surface of the reflected light 35 in the light receiving step 1003, the reflected light ( It is determined that the area 201 where the intensity of 35 is greater than the first predetermined value 41 and less than the second predetermined value 42 is an area where adjacent cracks of the peeling layer 110 are connected, and the reflected light 35 It is determined that the area 202 where the intensity of ) is greater than the second predetermined value 42 is an area where the wafer is separated from the workpiece 100 starting from the peeling layer 110, and the workpiece 100 is peeled off. The state of the peeling layer 110 on the entire surface of the layer 110 is a state in which cracks are connected to each other or the wafer is peeled off, that is, on the entire surface of the peeling layer 110 of the workpiece 100. It is determined that the state of the peeling layer 110 is a state in which at least cracks are connected to each other.

The method for inspecting a workpiece according to the first embodiment is such that, in the judgment step 1004, the determination unit 40 determines the peeling layer ( When it is determined that the state of 110) is that at least the cracks are connected (YES in step 1005 in FIG. 3), the process proceeds to the peeling step 1006, and an external force is applied to the workpiece 100. A peeling step 1006 of peeling the wafer from the workpiece 100 using the peeling layer 110 as a starting point is further performed.

On the other hand, in the inspection method of the workpiece according to the first embodiment, in the determination step 1004, the determination unit 40 determines the peeling layer 110 in at least a portion of the peeling layer 110 of the workpiece 100. ) When it is determined that the state is at least a state in which the cracks are not connected (NO in step 1005 in FIG. 3), the process is terminated and, for example, the process from the peeling layer forming step 1001 is reviewed. Urge the operator to do so.

The peeling step 1006 is a step of applying an external force to the workpiece 100 to peel the wafer from the workpiece 100 using the peeling layer 110 as a starting point. In the first embodiment, the external force is, for example, ultrasonic vibration applied by the peeling device 60 described later, but the present invention is not limited to this and is applied to the workpiece 100 starting from the peeling layer 110. ) Any force may be used as long as it is possible to peel the wafer from the wafer.

10 and 11 are perspective views illustrating the peeling step 1006 in FIG. 3. In the first embodiment, the peeling step 1006 is performed using the peeling device 60 shown in FIGS. 10 and 11 . As shown in FIGS. 10 and 11, the peeling device 60 includes a holding table 61 that holds the workpiece 100 with a holding surface 62, an arm 63, and a motor 64. , a disc-shaped adsorption piece 65, a liquid supply unit not shown, an ultrasonic vibration imparting means not shown, a movement unit not shown, and a controller not shown.

The holding table 61 is, for example, a chuck table that exposes the upper surface 101 side of the workpiece 100 on the holding surface 62 and holds it by suction from the lower surface 102 side. The arm 63 is formed to extend horizontally. The motor 64 is formed in a disk shape and is provided at the tip of the arm 63. The disc-shaped suction piece 65 is installed on the lower surface of the motor 64 so as to be rotatable around its axis, and adsorbs the workpiece 100 from the lower surface. The liquid supply unit supplies liquid between the upper surface 101 of the workpiece 100 and the ultrasonic vibration applying means disposed to face the upper surface 101 of the workpiece 100. The ultrasonic vibration applying means applies ultrasonic vibration to the workpiece 100 from the upper surface 101 side through the liquid supplied by the liquid supply unit from the lower surface.

The moving unit moves the holding table 61 and the workpiece 100 held on the holding table 61, the arm 63, the motor 64, and the suction piece 65 relative to each other in the X-axis direction and the Y-axis. Move along the Z-axis direction. In addition, the moving unit moves the holding table 61 and the workpiece 100 held on the holding table 61, the liquid supply unit, and the ultrasonic vibration applying means relative to each other in the X-axis direction, Y-axis direction, and Z-axis direction. Move along.

The controller of the peeling device 60 controls the operation of each component of the peeling device 60 and causes the peeling device 60 to perform the peeling step 1006. The controller of the peeling device 60 includes the same computer system as the controller of the inspection device 1. In addition, the ultrasonic vibration applying means is not limited to this form, and may be built into the suction piece 65 and apply ultrasonic vibration from the lower surface of the suction piece 65.

In the peeling step 1006, first, the controller of the peeling device 60 transfers the workpiece 100 after performing the peeling layer forming step 1001 onto the holding table 61 by a transfer unit (not shown), etc. 10, the workpiece 100 is held by the holding table 61.

In the peeling step 1006, the controller of the peeling device 60 applies the lower surface of the ultrasonic vibration applying means to the upper surface 101 of the workpiece 100 held on the holding table 61 by the moving unit. The ultrasonic vibration applying means is moved to the position, and the liquid supply unit is moved to a position where the liquid supply port of the liquid supply unit is directed between the upper surface 101 of the workpiece 100 and the lower surface of the ultrasonic vibration applying means. .

In the peeling step 1006, the controller of the peeling device 60 supplies liquid between the upper surface 101 of the workpiece 100 and the lower surface of the ultrasonic vibration applying means by the liquid supply unit, while ultrasonic vibration is applied. Ultrasonic vibration is applied to the workpiece 100 from the upper surface 101 side through the liquid supplied by the liquid supply unit by the applying means.

In the peeling step 1006, after applying the ultrasonic vibration, the liquid supply unit and the ultrasonic vibration applying means are retracted from the workpiece 100 held on the holding table 61 by the moving unit.

In the peeling step 1006, the controller of the peeling device 60 uses a moving unit to place the suction piece 65 on the holding table 61, as shown in FIG. 11 . It is moved to a position in contact with the upper surface 101 of the workpiece 100 held in ). In the peeling step 1006, the controller of the peeling device 60 adsorbs the upper surface 101 of the workpiece 100 on the lower surface of the suction piece 65 using the suction piece 65, and the motor 64 ) to rotate the suction piece 65.

In the peeling step 1006, the ultrasonic vibration previously applied and the external force generated by this rotation are used to separate the upper surface 101 from the workpiece 100 with the peeling layer 110 as a starting point. A wafer with a thickness equivalent to the depth 120 can be peeled.

In addition, in the peeling step 1006, the present invention is not limited to this, and when the ultrasonic vibration imparting means is built into the suction piece 65, the controller of the peeling device 60 is operated by a moving unit, as shown in FIG. 11 As shown, after moving the suction piece 65 to a position where the lower surface of the suction piece 65 is in contact with the upper surface 101 of the workpiece 100 held on the holding table 61, the suction piece ( The upper surface 101 of the workpiece 100 is adsorbed from the lower surface of the suction piece 65 by 65, and the upper surface 101 of the workpiece 100 is adsorbed from the lower surface of the suction piece 65 by ultrasonic vibration imparting means. By applying ultrasonic vibration toward and rotating the adsorption piece 65 by the motor 64, the depth ( A wafer with a thickness equivalent to 120) may be peeled.

In addition, the peeling step 1006 is not limited to the form of using the above-described peeling device 60 in the present invention, and for example, the upper surface ( The 101) side is exposed, immersed and placed in a water tank filled with enough water, and ultrasonic waves are oscillated from an ultrasonic oscillation member positioned above the upper surface 101 of the workpiece 100, and these ultrasonic waves transmit sound through the water in the water tank. By stimulating the peeling layer 110, a wafer with a thickness corresponding to the depth 120 including the upper surface 101 may be peeled from the workpiece 100, starting from the peeling layer 110.

In addition, the inspection method of the workpiece according to the first embodiment performs the peeling step (1006) based on the determination result of the determination step (1004), but the present invention is not limited to this and the determination step (1004) Regardless of the determination result, the process may be terminated without performing the peeling step (1006).

The inspection method and inspection device 1, 1-2 for a workpiece according to the first embodiment having the above-described configuration penetrates the workpiece 100 (Si ingot) and forms a peeling layer 110 ( By irradiating the entire surface of the upper surface 101 of the workpiece 100 with light 25 of a wavelength reflected from a crack, and observing the intensity of the reflected light 35 reflected from the peeling layer 110, , the state of the peeling layer 110 inside the workpiece 100 is determined.

For this reason, the inspection method and inspection device 1, 1-2 of the workpiece 100 according to the first embodiment irradiates the entire upper surface 101 of the workpiece 100 with the light 25 once. Since the state of the peeling layer 110 can be determined on the entire surface of the peeling layer 110 just by itself, regardless of the size of the workpiece 100, the peeling layer 110 can be removed in a short time without reducing productivity. Judgment becomes possible.

In addition, the inspection method and inspection device 1, 1-2 of the workpiece according to the first embodiment determines the formation status of the peeling layer 110, more specifically, the adjacent area, based on the intensity of the reflected light 35. Since it is possible to determine whether the cracks are connected to each other or whether the connected cracks are expanded and the ingot side and the wafer side of the workpiece 100 are separated, the peeling layer 110 is not affected by saw marks. It shows the effect of being able to determine the status of.

In addition, the inspection method and inspection device 1, 1-2 of the workpiece according to the first embodiment determines whether the intensity of the reflected light 35 is greater than the first predetermined value 41, and the peeling layer 110 Since it is determined whether or not adjacent cracks are connected to each other, it is possible to determine whether or not adjacent cracks are connected to each other efficiently in a short time and with high precision without being affected by saw marks.

In addition, the inspection method and inspection device 1, 1-2 for a workpiece according to the first embodiment allows the intensity of the reflected light 35 to be greater than the second predetermined value 42, which is greater than the first predetermined value 41. Since it is determined whether or not the wafer is peeling from the workpiece 100 using the peeling layer 110 as a starting point, it is possible to efficiently determine whether the ingot side and the wafer side of the workpiece 100 are peeling in a short time. This allows judgment to be made with high precision without being affected by saw marks.

In addition, the inspection method and inspection device 1, 1-2 of the workpiece 101 according to the first embodiment includes the processing transfer direction, which is the direction in which the laser beam 58 is irradiated, and the upper surface 101 of the workpiece 100. Since the light 25 is irradiated to the upper surface 101 of the workpiece 100 at a predetermined angle of incidence from a direction parallel to the plane perpendicular to ), the reflected light 35 is light reflected by the crack. By suppressing the flickering, the reflected light 35 received by the light receiving unit 30 in the light receiving step 1003 to be performed later can be made clearer, thereby making a judgment based on the intensity of the reflected light 35. It can be carried out more clearly.

In addition, in the inspection method of the workpiece according to the first embodiment, when it is determined in the determination step 1004 that adjacent cracks in the peeling layer 110 are connected, the peeling step 1006 is further performed. , the peeling process of the wafer can be carried out efficiently.

In addition, the inspection method of the workpiece according to the first embodiment alternates the peeling layer forming step (1001) with the laser beam irradiation step (1011) and the indexing transfer step (1012), thereby forming the workpiece ( Since the peeling layer 110 including a plurality of modified layers and cracks is formed inside the 100), the upper surface is formed near the convergence point 59 of the laser beam 58 along a plurality of lines parallel to the processing transfer direction. Since a modified layer parallel to (101) can be formed and cracks can be connected to each other by extending cracks from the modified layer formed along adjacent lines, these modified layers and cracks can be contained by applying a predetermined external force. Starting from the peeling layer 110, it is possible to peel a wafer with a thickness equivalent to the depth 120 including the upper surface 101 from the workpiece 100.

In addition, since the inspection device 1-2 according to the first embodiment has at least two light sources 20, it is possible to obtain the amount of light 25 and the upper surface of the workpiece 100. Since the uniformity of the light 25 irradiated to the entire surface of 101 is improved, the amount of reflected light 35 received by the light receiving unit 30 can be obtained, and the workpiece 100 can be peeled off. The uniformity of the reflected light 35 from the crack contained in the entire surface of the layer 110 can be improved, thereby determining the state of the peeling layer 110 of the workpiece 100 by the judgment unit 40. The precision of judgment can be improved.

[Second Embodiment]

The inspection method of a workpiece according to the second embodiment of the present invention will be explained based on the drawings. Fig. 12 is a flowchart showing the processing sequence of the inspection method for a workpiece according to the second embodiment. In Fig. 12, the same parts as those in the embodiment are given the same reference numerals and description is omitted.

As shown in FIG. 12, the inspection method of the workpiece according to the second embodiment determines in the first embodiment that adjacent cracks of the peeling layer 110 are connected in the determination step 1004. In this case, instead of performing the peeling step 1006, the peeling layer forming step 1001 is performed and then the peeling step 1006 is further performed, and the wafer is peeled from the workpiece 100 in the peeling step 1006. In the case where it could not be done (NO in step 1007 in FIG. 12), the irradiation step 1002, the light receiving step 1003, and the judgment step 1004 were changed to be performed. The other configuration is the same as the first embodiment. Same thing.

Even if the peeling step 1006 is performed, the workpiece 100 is removed from the workpiece 100 due to the fact that there are parts where the peeling layer 110 is not formed on the inner surface of the workpiece 100 parallel to the upper surface 101. There are cases where the wafer cannot be peeled. In the method of inspecting a workpiece according to the second embodiment, when the wafer cannot be peeled from the workpiece 100 in the peeling step 1006 (NO in step 1007 of FIG. 12), the inspection step is performed. (1002), the light receiving step (1003) and the decision step (1004) are performed. For example, in the decision step (1004), the wafer is peeled from the workpiece 100 starting from the peeling layer 110. It is to determine whether it exists or not. Additionally, in the method for inspecting a workpiece according to the second embodiment, if the wafer can be peeled from the workpiece 100 in the peeling step 1006 (YES in step 1007 of FIG. 12), the process is terminated. do.

In the method of inspecting a workpiece according to the second embodiment, after performing the peeling layer forming step 1001, an external force is applied to the workpiece 100 to separate the workpiece 100 from the peeling layer 110 as a starting point. A peeling step 1006 of peeling the wafer from the workpiece 100 is further performed, and when the wafer cannot be peeled from the workpiece 100 in the peeling step 1006, the irradiation step 1002, the light receiving step 1003, and the judgment step are performed. (1004) is carried out. In this way, in the inspection method of the workpiece according to the first embodiment, the irradiation step 1002, the light reception step 1003, and the judgment step 1004 are performed only when there is a possibility that a problem may occur in the peeling layer 110. Therefore, the state of the peeling layer 110 can be determined efficiently.

Additionally, the present invention is not limited to the above embodiments. In other words, the present invention can be implemented with various modifications without departing from the gist of the present invention.

1, 1-2 inspection device
10 holding table
20 light source
25 light
30 light receiving units
35 reflected light
40 judgment units
41 First predetermined value
42 Second predetermined value
58 laser beam
59 Concentrating point
100 Workpiece
101 upper surface
102
110 peeling layer
120 depth

Claims (11)

A method for inspecting a workpiece made of single crystal silicon manufactured so that a specific crystal plane included in the crystal plane {100} is exposed on each of the upper and lower surfaces, comprising:
The condensing point of the laser beam having a wavelength that is transparent to the workpiece is positioned at a depth corresponding to the thickness of the wafer to be manufactured from the upper surface of the workpiece, and the focus point and the workpiece are moved in a relative processing transfer direction. A peeling layer forming step of irradiating a laser beam while moving to form a modified layer parallel to the upper surface inside the workpiece and a crack extending from the modified layer;
After performing the peeling layer forming step, an irradiation step of irradiating light of a wavelength that transmits through the workpiece and is reflected from cracks in the peeling layer to the entire upper surface of the workpiece on which the peeling layer is formed;
a light receiving step of receiving reflected light irradiated in the irradiation step and reflected by the crack;
A determination step of determining the state of the peeling layer based on the intensity of the reflected light received in the light receiving step.
A method for inspecting a workpiece, comprising: According to paragraph 1,
In the determination step, it is determined whether or not adjacent cracks in the peeling layer are connected to each other based on whether the reflected light intensity is greater than a first predetermined value,
When it is determined in the determination step that the adjacent cracks in the peeling layer are connected to each other, an external force is applied to the workpiece to peel the wafer from the workpiece using the peeling layer as a starting point. , method of inspecting the workpiece. According to paragraph 1,
After performing the peeling layer forming step, a peeling step of applying an external force to the workpiece to peel the wafer from the workpiece using the peeling layer as a starting point,
A method for inspecting a workpiece, wherein when the wafer cannot be peeled from the workpiece in the peeling step, the irradiation step, the light receiving step, and the determination step are performed again. According to paragraph 3,
In the determination step, the intensity of the reflected light is determined by whether or not the intensity of the reflected light is greater than a second predetermined value that is greater than the first predetermined value, which is a criterion for determining whether adjacent cracks in the peeling layer are connected and formed, starting from the peeling layer. A method for inspecting a workpiece, characterized in that it determines whether or not the wafer is separated from the workpiece. According to any one of claims 2 to 4,
The peeling layer forming step is,
A laser beam is irradiated while relatively moving the convergence point of the laser beam and the workpiece along a direction parallel to the crystal orientation <100>, and the inside of the workpiece is separated from the modified layer parallel to the upper surface and the modified layer. A laser beam irradiation step to form an extending crack,
An indexing transfer step of relatively indexing and transferring the converging point of the laser beam and the workpiece in a direction perpendicular to the direction in which the modified layer was formed in the laser beam irradiation step.
A method for inspecting a workpiece, wherein a peeling layer containing a plurality of modified layers and cracks is formed inside the workpiece by performing the steps alternately. According to clause 5,
The light irradiated in the irradiation step is irradiated to the upper surface of the workpiece at a predetermined angle of incidence from a direction parallel to a plane perpendicular to the upper surface of the workpiece, including the processing transfer direction. method of inspection. A laser beam having a penetrating wavelength is irradiated from the upper surface side to a workpiece made of single crystal silicon manufactured so that a specific crystal plane included in the crystal plane {100} is exposed on the upper and lower surfaces, respectively, to the inside of the workpiece. An inspection device for inspecting the peeling layer of a workpiece on which a peeling layer consisting of a modified layer and cracks extending from the modified layer is formed,
A holding table that exposes the upper surface of the workpiece to hold the workpiece,
a light source that irradiates light of a wavelength that passes through the workpiece and is reflected from the crack to the entire upper surface of the workpiece held on the holding table;
a light receiving unit that is illuminated by the light source to the entire upper surface of the workpiece and receives reflected light reflected from the crack included in the peeling layer;
A judgment unit that determines the state of the peeling layer based on the intensity of reflected light received by the light receiving unit.
Equipped with an inspection device. In clause 7,
The inspection device wherein the determination unit determines whether adjacent cracks in the peeling layer are connected and formed based on whether or not the reflected light intensity is greater than a first predetermined value. In clause 7,
The determination unit determines whether or not the reflected light intensity is greater than a second predetermined value that is greater than a first predetermined value, which is a judgment standard for whether or not adjacent cracks in the peeling layer are connected and formed, with the peeling layer as a starting point. An inspection device that determines whether or not the wafer is separated from the workpiece. According to any one of claims 7 to 9,
The workpiece is irradiated with a laser beam along a direction parallel to the crystal orientation <100> to form a peeling layer including a modified layer parallel to the upper surface and cracks extending from the modified layer,
The light source is located at a position capable of irradiating light to the upper surface of the workpiece at a predetermined angle of incidence from a direction parallel to a plane perpendicular to the top surface of the workpiece, including the processing transport direction, which is the direction in which the laser beam is irradiated. An inspection device that is deployed. According to clause 10,
An inspection device wherein the light sources are at least two.